The present invention relates to a new and distinct cultivar of pummelo tree, botanically known as Citrus grandis, and hereinafter referred to by the name ‘5-1-99-5’. Cultivar ‘5-1-99-5’ is a red pummelo selected from a group of open-pollinated seedlings obtained from the ‘Hirado Buntan Pink’ pummelo (female parent), currently the most popular variety and the only commercially significant pummelo in Florida. Fruit of ‘5-1-99-5’ is quite different from that of ‘Hirado Buntan’. The fruit flesh is light pink for ‘Hirado Buntan’, and an attractive dark red for ‘5-1-99-5’. Fruit rind of relatively thin for both of these pummelos as compared to pummelos in general, but ‘5-1-99-5’ generally has a thinner rind than ‘Hirado Buntan’. Fruit shape is also different, as ‘Hirado Buntan’ generally has a flatter fruit than ‘5-1-99-5’, which is a bit more oblong. Fruit size is quite uniform for ‘5-1-99-5’ and quite variable for ‘Hirado Buntan’. Average fruit size is larger for ‘5-1-99-5’. Flavor also differs, with ‘5-1-99-5’ having more of a hint of ‘grapefruit’ flavor. ‘5-1-99-5’ was asexually propagated by standard inverted-T grafting to sour orange+Carrizo somatic hybrid rootstock and planted in Lake Alfred, Fla., where trees demonstrated all the characteristics of the original plant.